$\alpha$ -carbon of $\alpha$ -amino acid is asymmetric
All proteins are found in $\mathrm{L}$ -form
Human body can synthesize all proteins they need
At pH $=7$ both amino acids and carboxylic groups exist in the ionised form
Solution
Amino acids are organic compounds that contain amine $(-\mathrm{NH} 2)$ and carboxyl (-COOH) functional groups, along with a side chain (R group) specific to each amino acid. a -carbon of cc-amino acid is asymmetric. Hence this statement is true. Proteins exist in both D and L-form. So, option (2) is an incorrect statement. The body synthesizes all of its own proteins. The proteins that you obtain through your food are broken down in the digestive system into individual amino acids, which enter the blood stream in the small intestine. From there, they are transported by the blood stream into cells, where they are reassembled into new proteins with the help of ribosomes. This is necessary because proteins are specialized molecules that have to be built in a precise manner in order to perform their function. At $\mathrm{pH}=7$, both amino and carboxylic groups exist in ionised form i.e. zwitter ion.